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A038050
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Number of labeled rooted trees with 3-colored leaves.
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2
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3, 6, 45, 504, 7785, 153468, 3681909, 104126256, 3392064945, 125089571700, 5151335388309, 234322765501608, 11668410187187481, 631335472193760012, 36881146426978035765, 2313552152470193124192, 155107536736245864549345
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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REFERENCES
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F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 185 (3.1.83)
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LINKS
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Table of n, a(n) for n=1..17.
Index entries for sequences related to rooted trees
N. J. A. Sloane, Transforms
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FORMULA
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Divides by n and shifts left under exponential transform.
E.g.f.: 2*x-LambertW(-x*exp(2*x)). - Vladeta Jovovic, Mar 09 2003
a(n) = Sum_{k=0..n} (binomial(n, k)*2^k*(n-k)^(n-1)).
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CROSSREFS
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Cf. A000169, A029857.
Cf. A038049.
Sequence in context: A203434 A076170 A137775 * A194080 A197884 A032322
Adjacent sequences: A038047 A038048 A038049 * A038051 A038052 A038053
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KEYWORD
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nonn,eigen
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AUTHOR
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Christian G. Bower, Jan 04 1999.
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STATUS
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approved
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